Sphygmomanometers are commonly known and established medical diagnostic instruments used for measuring the blood pressure of a patient. In one well known version, a reusable cuff or sleeve made from fluid-impermeable materials is wrapped about the limb (e.g., arm or leg) of the patient. Various sized sleeves are made, depending upon the class (i.e., child, adult, neonatal) of the patient. Most sleeves of this type are defined by either a pair of planar sheets that are sealed together or are formed of a single sheet, the sleeve either having a contained bladder or an inflatable interior compartment. The sleeves further typically include hook and loop fasteners disposed at specific locations on opposing sides in order permit releasable and adjustable attachment to a patient, as well as removal therefrom. The bladder or interior inflatable compartment is inflated using pneumatic means, such as a pump, which is tethered to the cuff by means of a flexible hose attached to a barb that is provided on the exterior of the sleeve. Pressure variations in the sleeve can then be detected by a gage housing having a dial indicator that is attached to the cuff. In mechanical versions, the gage housing contains a movement mechanism having a pressure responsive element, such as a diaphragm, wherein pressure variations are imparted to the dial indicator on the gage housing, according to the well-known oscillometric technique. Electronic blood pressure measuring versions, which may or may not include a pump directly within the gage housing, are also known such as those manufactured and sold by Welch Allyn, Inc. and Omron Corporation, among others, the results being displayed for example, using an LCD. In these latter types of devices, either the oscillometric (pulsatile) or auscultory method of pressure measurement can be utilized, the latter being used in combination with a stethoscope or microphone.
These diagnostic instruments are repletely found in a doctor's office or within examination rooms found in a medical facility or hospital. With regard to a medical facility or hospital and depending upon the number of procedures that are performed on a patient during an examination or a typical hospital or urgent care facility visit, there are compelling reasons why a blood pressure sleeve should not be reused, for example, the potential for cross contamination of infectious fluids between patients, among others.
To that end, efforts have been made to create “single use” or “single patient” blood pressure cuffs that can be used either a single time or over the course of an entire hospital visit for a patient. Exemplary versions of these cuffs are described, for example, in U.S. Patent Application Publication No. 2010/0298725 A1 filed on Feb. 12, 2010, and entitled “Recyclable or Biodegradable Blood Pressure Cuff”, U.S. Patent Publication No. 2010/0298724 A1, and entitled “Recyclable or Biodegradable Blood Pressure Cuff, filed on May 19, 2009, U.S. Patent Application Publication No. 2012/0150051 A1, entitled “Blood Pressure Cuff” and filed on Dec. 9, 2009, the entire contents of each of these documents being relied upon and incorporated by reference in their entirety. As to electronic blood pressure measuring apparatus, a detailed description of an exemplary embodiment of an electronic apparatus for the non-invasive measurement of blood pressure is presented in commonly owned U.S. Pat. No. 7,429,245, issued on Sep. 30, 2008, and entitled “Motion Management in a Fast Blood Pressure Measurement Device”. This latter device advantageously measures blood pressure during inflation of the blood pressure sleeve as opposed to step-down deflation measurements, which are commonly known. As a result, measurement results can be obtained more expediently and with less anxiety for the patient, among other benefits.
The creation of an inexpensive single use or single patient blood pressure cuff can include fabrication from a single material, such as polyethylene or polypropylene, that promotes recyclability. According to one exemplary version, an inflatable portion is created between two sheets of a single type of material that are attached through welding or other securing means in which a fluid impermeable compartment is formed. A port or socket provided in an opening of the inflatable portion enables the attachment of pneumatic means, as previously described, to permit inflation. The inflatable compartment is initially and circumferentially wrapped about the limb (e.g., the arm) of the patient and an axially extending portion of the cuff is further wrapped about the inflatable portion, the axially extending portion of the cuff including a slotted portion that is sized to receive the extending port. These sleeves, as developed, function properly when used to take conventional blood pressure measurements during the step-down deflation phase of the measurement cycle. However and in attempting to reliably utilize cuffs of this type for measuring blood pressure during the inflation cycle, numerous problems have been encountered. One such problem is discussed in U.S. Patent Application Publication No. 2012/0150051 A1, relating to lobeing or pillowing of the inflatable portion or a bladder added to define an inflatable chamber, in which increases in inflation pressure can cause a lobed portion to undesirably “pop” or release during the inflation period.
In the course of developing single use or single patient cuffs, another problem that has been encountered involves a frictional “stick-slip” between sliding surfaces of the wrapped sleeve. In one version, the wrapped cuff includes a hook fastener portion at one end of an axial extending portion of the cuff opposite from the inflatable portion of the cuff that is preferably made from the same material as the remainder of the cuff. The hook fastener portion acts in concert with a non-woven side of the sleeve, the latter including a series of interlaced fibers that behave as loop fasteners when engaged by the hook fastener portion to act as closure means for the sleeve when wrapped. In the course of wrapping the sleeve about the inflatable portion and advancing the slotted portion to the port, the bottom surface of the axial extending portion of the sleeve is in sliding contact against the wrapped non-woven surface. It has been determined that the frictional interaction between these surfaces changes, for example, as the sleeve is inflated. To that end, the character of this cuff design is such that the static and dynamic coefficients of friction between the contacting surfaces vary. In addition, the dynamic coefficient of friction also varies on its own based on load, such as during inflation of the cuff. These changes produce a “stick then slip” characteristic, as opposed to a continuous and predictable inflating action of the wrapped cylinder, which can invariably introduce undesirable noise into the resulting measurement signal and affect overall accuracy.
Therefore, there is a need to create a disposable or recyclable blood pressure cuff design that can be advantageously used to reduce noise when the cuff is used, including during inflation. However and to date such incorporation has not been possible for numerous reasons, such as the above-noted frictional effects that are created by a single material wrappable cuff design.